1. Field of the Invention
The invention relates to an improved fuel injection nozzle for an internal combustion engine and more particularly to such a nozzle having two coaxial nozzle needles.
2. Description of the Prior Art
From German Patent Disclosure DE 40 23 223 A1, a fuel injection nozzle with two nozzle needles disposed coaxially to one another is known. One common nozzle needle seat for both nozzle needles is provided in the valve body surrounding the nozzle needles. Consequently, both when the first nozzle needle is opened and when the second nozzle needle is opened, fuel is injected into the combustion chamber at an angle of 60°, for instance, to the longitudinal axis of the fuel injection nozzle. These injection angles are necessary, in the so-called heterogeneous operating mode of the engine.
In some load states of the engine, however, it is advantageous if the fuel is injected into the combustion chamber in the direction of the longitudinal axis of the fuel injection nozzle (homogeneous mode).
In International Patent Disclosure WO 02/18775, the distinction between the aforementioned homogeneous mode and the heterogeneous mode of an internal combustion engine is explained in detail. This explanation is hereby incorporated by reference.